1. Field of the Invention
The present invention relates generally to laser printers and particularly to laser printers having front and rear doors.
2. Description of the Background Art
A conventional laser printer 101, as shown in FIGS. 10 and 11, has a front side with a front door 102 that can be opened and closed to handle sheet jams, exchange toner, and for similar maintenance. Laser printer 101 has a rear side with a rear door 104 opposite front door 102. Rear door 104 has an inner side provided with a sheet feed guide 104b feeding a sheet (not shown), accommodated in a tray 103, along an arrow to a printing unit 108.
Laser printer 101 is previously set so that closing front door 102 allows a toner cartridge (not shown) to be housed at a predetermined position. If the laser printer operates with front door 102 open, the toner cartridge is not housed at the predetermined position, and laser printer 101 has toner leaking therein, which can result in poor printing.
In contrast, if the laser printer operates with rear door 104 open, a sheet output from tray 103 would not be guided toward printing unit 108. Consequently, the sheet would cause a jam or be discharged outside laser printer 101.
Accordingly laser printer 101 is required to operate with front and rear doors 102 and 104 both closed. Japanese Patent Laying-Open Nos. 2001-125331, 2002-72601 and 2002-187324 propose a printer provided with a sensor detecting that doors provided at two adjacent side portions, respectively, are closed.